\\[-1.8ex] Soil Heterogeneity & $-$0.430$^{***}$ & $-$0.413$^{***}$ & $-$0.371$^{***}$ & $-$0.322$^{***}$ \\ 
  & (0.128) & (0.128) & (0.115) & (0.113) \\ 
\\[-1.8ex] 
Observations & 17,203 & 17,203 & 17,021 & 17,021 \\ 
R$^{2}$ & 0.417 & 0.419 & 0.431 & 0.441 \\ 
